Solutions to text problems

Quick Quizzes

1. The price elasticity of demand is a measure of how much the quantity demanded of a good responds to a change in the price of that good, computed as the percentage change in quantity demanded divided by the percentage change in price.

The relationship between total revenue and the price elasticity of demand is: (1) when demand is inelastic (a price elasticity less than 1), a price increase raises total revenue, and a price decrease reduces total revenue; (2) when demand is elastic (a price elasticity greater than 1), a price increase reduces total revenue, and a price decrease raises total revenue; and (3) when demand is unit elastic (a price elasticity equal to 1), a change in price does not affect total revenue.

2. The price elasticity of supply is a measure of how much the quantity supplied of a good responds to a change in the price of that good, computed as the percentage change in quantity supplied divided by the percentage change in price.

The price elasticity of supply might be different in the long run than in the short run because over short periods of time, firms cannot easily change the size of their factories to make more or less of a good. Thus, in the short run, the quantity supplied is not very responsive to the price. However, over longer periods, firms can build new factories, expand existing factories, or close old ones, or they can enter or exit a market. So, in the long run, the quantity supplied can respond substantially to the price.

3. A drought that destroys half of all farm crops could be good for farmers (at least those unaffected by the drought) if the demand for the crops is inelastic. The shift to the left of the supply curve leads to a price increase that raises total revenue because the price elasticity is less than one.

Even though a drought could be good for farmers, they would not destroy their crops in the absence of a drought because no one farmer would have an incentive to destroy his crops, since he takes the market price as given. Only if all farmers destroyed their crops together, for example through a government program, would this plan work to make farmers better off.